单项选择题 The output of the show aaa domain-map displays the following information: Domain: isp1.com; virtual-router: vr1; loopback: 1 Domain: isp2.com; virtual-router: vr2; loopback: 1 Domain: none; virtual-router: vr3; loopback: 1 Domain: default; virtual-router: vr4; loopback: 1 The end user supplies a login name of joe@isp7.com . Which virtual router is responsible for authenticating this user?（）

单项选择题 The output of the show aaa domain-map displays the following information: Domain: isp1.com; virtual-router: vr1; loopback: 1 Domain: isp2.com; virtual-router: vr2; loopback: 1 Domain: none; virtual-router: vr3; loopback: 1 Domain: default; virtual-router: vr4; loopback: 1 The end user supplies a login name of joe with no domain name. Which virtual router is responsible for authenticating this user?（）

单项选择题 When does the E-series router start monitoring DHCP traffic using the DHCP External function?（）